What will happen to the poles?

If ice loss continued at a steady rate, we would have ice-free summers in the Arctic by about 2100 [1]. Yes, really. Even worse, ice melt is accelerating [2]. This means it might happen as early as 2050 [3]. Yes, really. The science behind this follows below:

Imagine pushing a glass of water off balance – before the TIPPING POINT it will return to standing, beyond the tipping point it will fall over and spill the water. For ice melt, at a tipping point, a small amount of temperature change causes a much larger loss of ice [3].

You know how black things heat up really fast when in the sun, but white things don’t? This is an issue here too: white ice reflects a lot of sunlight, whilst the ocean is a much darker colour and so reflects less sunlight. So when ice melts to expose dark sea, this makes Earth warm up faster [4, 5]. It gets worse: this additional warming results in a ‘positive-feedback loop’: warmer atmosphere melts ice, which exposes the dark ocean, which warms the atmosphere more, which melts more ice, and so on [5].

Some scientists think we have already passed this tipping point for Arctic ice [1], so we may have summers with no Arctic ice before 2050 (rather than 2100) [3]. Once past the tipping point, it is harder for ice to reform than it is to melt [3].

SLIPPING ICE: When floating ice melts, it may not add much to sea level rise directly [6,11], but it can destabilise ice on land [7]. Much of the West Antarctic Ice Sheet (WAIS) is on rock sloping downwards inland, meaning that in theory a small amount of ice melt at the base could cause the ice to slide off and float upwards, disintegrating fast [8,9]. This is another tipping point, and it could cause rapid loss of the WAIS [7].

Loss of the whole WAIS would lead to around 5m of sea level rise [10]. We have to fix this.